1. Field of the Invention.
The subject invention relates to a coaxial connector assembly that enables quick connection for high frequency signal transmission.
2. Description of the Related Art.
A prior art coaxial cable comprises an inner conductor, an insulation material surrounding the inner conductor, an outer conductor surrounding the insulation material and an outer insulating sheath surrounding the outer conductor. The inner conductor is used for carrying signals, and often very high frequency signals. The outer conductor functions as a shield to prevent a degradation of the signal carried by the inner conductor.
The prior art coaxial cable typically is connected to an electrical apparatus that generates or receives the signal carried by the cable. A large number of coaxial cables may lead into and/or out of the electrical apparatus. Each cable must have a secure mechanical and electrical connection of both the inner and outer conductors to the apparatus to ensure that the signal is not degraded at the connection.
Signal generating or processing devices often are reconfigured, updated or repaired. Such changes typically require the coaxial cables to be disconnected and then reconnected. As a result, the connections between coaxial cables and the signal generating or processing apparatus can not be a permanent connection, and coaxial connectors are used to mate a coaxial connector to a signal processing or generating apparatus. A coaxial connector must perform several functions, and the relative importance of the functions will vary depending upon the environment in which the connector is used. More particularly, a coaxial connector must enable transmission of the signal across the mated inner conductors. The coaxial connector also must achieve and maintain a ground across the outer conductors for efficient shielding. The connectors also must be engaged securely with one another and must be capable of periodic disconnection and reconnection.
Coaxial connectors frequently are used with home entertainment equipment. The ease of connection and disconnection of coaxial connectors in this environment is less important because disconnection and reconnection occurs relatively infrequently and because the owner of such equipment typically will not be under time pressure to make a rapid disconnection and reconnection.
Other coaxial connectors are used in a high vibration environment. In these situations, it is important to provide a connection that will not disengage in response to vibrations.
Still other coaxial connectors are used for very high frequencies. In these situations, convenience of disconnection and reconnection may be sacrificed to ensure an ability to carry high frequency signals across the connector without significantly affecting the quality of the signal.
The size and signal carrying ability of a coaxial connector often is quantified by standards developed for the military. In particular, military specifications define dimensional and performance standards for a Sub-Miniature Series A connector. Connectors that meet this standard have many non-military applications and are identified commercially as SMA coaxial connectors. A typical prior art SMA connector assembly includes one connector with an externally threaded outer shell formed from a metallic material that forms a part of the ground or shield around the connector. The opposed connector has a metallic lock nut with an array of internal threads. The lock nut is engaged threadedly with the external threads on the shell of the mating connector and also is connected to the outer conductor on the cable. Thus, threaded engagement of the two mated connectors provides continuity of the outer conductor across the connection.
SMA connectors perform their signal carrying function very well and are employed widely throughout the telecommunication, computer and home entertainment industries. However, as noted above, many signal generating or processing devices have a large number of coaxial connectors. The connectors often are arrayed densely on a panel of the device and require connection to a corresponding number of coaxial cables. In a typical situation, the panel mounted connector on the signal processing device will have an outer shell formed with an array of external threads. A typical mating SMA connector will have a corresponding lock nut that must be threadedly engaged with the externally threaded outer shell on the panel of the signal processing device. The threaded connection of a large number of lock nuts on the coaxial cables to the threaded outer shells of the panel-mounted connectors requires a considerable amount of time and hence imposes a significant cost penalty in industries where such connections are connected and disconnected with some regularity. Additionally, the dense arrays of coaxial connectors on panels complicate the threaded connection and reconnection.
Some coaxial connectors are designed for push-pull connection, and hence do not require the physically cumbersome and slow process of threadedly connecting a lock nut of a cable mounted connector to a threaded outer shell of a panel mounted connector. However, many of these quick-connect push-pull connectors are specially manufactured and differ substantially from the SMA dimensional specifications. Additionally, most equipment manufacturers are reluctant to adopt an entirely new connector as an alternate to the widely accepted SMA connectors. Furthermore, many prior art quick-connect push-pull connectors are mechanically complex and costly. Other less expensive push-pull coaxial connectors provide poor signal carrying capability and have a mechanical connection that is unacceptable for high vibration environments.
Accordingly, an object of the subject invention is to provide a coaxial connector that can be connected and disconnected easily and that provides a high frequency signal carrying capability.
The subject invention is directed to an adaptor for a coaxial connector, such as an SMA coaxial connector. Additionally, the subject invention is directed to a coaxial connector assembly with an adaptor that permits a mechanically secure quick connection/disconnection with an ability to carry high frequency signals.
The adaptor of the subject invention may be employed with a conventional prior art SMA female connector that may be mounted to the panel of a signal processing device. The connector includes a center conductor, a dielectric or an insulating material surrounding the center conductor and an outer conductor concentric with the center conductor. The outer conductor may be mounted to the panel of a signal processing device and is provided with a cylindrical outer shell having an array of external threads formed thereon.
The adaptor of the subject invention is a generally cylindrically tubular member formed from a metallic material, such as beryllium, with acceptable signal carrying characteristics. The adaptor includes a mounting end and an opposite mating end. The mating end may be characterized by an inwardly extending annular shoulder. Portions of the adaptor between the opposed ends include an array of internal threads dimensioned for threaded engagement with the external threads on the shell of the outer conductor of the prior art SMA connector. The outer surface of the adaptor is substantially smoothly cylindrical at most locations between the opposed mounting and mating ends. However, the outer cylindrical surface is characterized by an annular groove that preferably is disposed at a location closer to the mounting end of the adaptor.
The connector assembly of the subject invention further includes a coaxial connector that may be mounted to a coaxial cable. The coaxial connector includes a center contact surrounded by a dielectric or insulating material. A conductive plug body is mounted to and surrounds the insulator and concentrically surrounds the center contact of the coaxial connector. The plug body includes a rear mounting end that is connected to the outer conductor of the cable to provide a continuous shielding and grounding at the interface of the cable and the connector. The plug body also includes an annular undercut extending around the rear end.
A lock body surrounds the plug body and projects forwardly therefrom. More particularly, the lock body includes a rear mounting end and a front mating end. The rear mounting end may include an inwardly directed annular flange dimensioned and configured for secure permanent mating with the annular undercut at the rear of the plug body. Portions of the lock body that surround and engage the plug body may define a continuous cylinder that closely engages and retains outer circumferential surface portions of the plug body. An annular groove is formed in an outer circumferential surface of the lock body. The lock body further includes a plurality of resiliently deflectable fingers that project forwardly beyond both the center contact and plug body. The front ends of the fingers are characterized by inwardly directed beads dimensioned and configured for engaging in the circumferential groove in the outer surface of the adaptor. Additionally, the front ends of the fingers on the lock body have outwardly facing lock shoulders.
The connector assembly further includes a locking ring that surrounds the lock body and that is axially movable thereon. The locking ring includes a continuous annular forward end that surrounds and engages shoulders of the forward ends of the locking fingers of the lock body. Thus, the annular front portion of the locking ring prevents the outward deflection of the fingers on the lock body that would be required for the lock body to engage with or disengage from the annular locking groove in the adaptor. The locking ring further includes a plurality of resiliently deflectable fingers that project rearwardly from the continuous annular front portion of the locking ring. The fingers include inwardly directed detents that engage in the annular groove formed in the rearward position on the lock body.
An axially directed rearward force on the locking ring will cause the resiliently deflectable fingers of the locking ring to bias outwardly and out of the locking groove on the lock body. Continued rearward forces on the locking ring then will permit axial movement of the locking ring relative to the lock body. Sufficient axial movement of the locking ring will cause the annular front locking portion of the locking ring to move rearwardly from the locking shoulders on the fingers of the lock body. Hence, the locking fingers of the lock body can deflect resiliently outwardly. Conversely, forward movement of the locking ring will position the annular front locking portion of the locking ring on the locking shoulders of the lock body and will position the detents on the locking fingers of the locking ring in the annular lock groove of the lock body.
The connector assembly of the subject invention is used by threadedly mounting the adaptor housings onto the standard SMA connectors. This threaded mounting can be carried out by automated equipment under factory conditions prior to mounting the female SMA connectors onto the panel of the signal processing device. The lock plug assembly then is permanently mounted to a cable substantially as with any prior art coaxial connector.
The plug assembly can be mounted to the adaptor on the SMA connector merely by pulling the lock ring rearwardly on the lock body sufficiently for the annular locking position front of the locking ring to clear the locking shoulders of the fingers on the lock body. The plug then can be mated with the assembled adaptor and SMA connector. In particular, the center contact of the plug is mated with the center contact of the SMA connector. The plug body then is telescoped into the front end of the shell of the SMA connector. Simultaneously, the resiliently deflectable fingers of the lock body telescope over the adaptor. Sufficient advancement will cause the inwardly directed beads on the fingers of the lock body to align with the lock groove on the adaptor. The fingers then will resiliently return toward and undeflected condition and into locking engagement with the lock groove on the adaptor. The locking ring then can be advanced forwardly toward the SMA connector, such that the continuous annular front end of the locking ring surrounds and engages the locking shoulders of the fingers on the lock body, and such that the inwardly directed detent on the rearwardly directed fingers of the locking ring engage in the annular lock groove near the rear end of the lock body.
The subject assembly enables connection of the plug with the standard SMA connector without threaded interconnection at the site of the mating. Additionally, the assembly enables a mechanically secure high frequency connection that can be completed quickly and easily.
Additionally, the locking engagement of the resilient fingers of the lock body and the lock ring provides a clear audible and tactile indication that a secure and complete mating has been effected.